Sternomental Displacement Test for Predicting Difficult Airway in Obese Patients

While the patient is in sitting position, (SMD neutral) will be is measured using tape as the distance between upper borders of the manubrium sterni to the mentum with the head in a neutral position. The (SMD extension) will be then measured in the same way with the head extended on the neck. The difference between SMD extension and SMD neutral will be then calculated as sternomental displacement (SMDD).